So I have a 16v battery that's about 2 years old. I'm trying to figure out if the charger or the battery is bad. Digital gauge in car says 16.8 volts, but when you try to spin it over it acts like the battery is dead. Put charger on and get 17.7 volts, leave it on for 5 min and car will start, make a pass and right back to the same thing. Car also has alternator on it.

When charging the battery what voltage should be going into the battery from the 16v charger?

Put a meter on the BATTERY POSTS, not the connectors, and try to crank it. If the voltage drops way down the battery is junk. If it doesn't you have a bad connection somewhere.

It's the battery.

16 volt batteries don't have the reserve a 12 volt does.

I had a 16 volt that did the same thing. I replaced it. New car has 2 12v and I don't plan to switch to 16v, since this car needs reserve, not starter speed.

I've ran it for 2 years with no issues. Its just weird. I have heard that sometimes the chargers fail and wont properly charge them. That's why I was wondering what the voltage rate should be coming out of the charger.

Who’s battery and charger? I had issue with XS batteries and also had a turbostart charger get a bad connection inside.

Its an XS Battery, I have 3 chargers. 2 Turbo Start chargers and when they are connected to the car will read 17.5 volts on my in car digital gauge while charging. The XS charger will read 18.9 volts when charging. With no chargers on the battery will read 16.2 ish

Sounds like your turbostart did same thing mine was doing. I opened it up and unplugged then replugged all the wires to clean up connections and it started working good again. I have XS charger now and carry the turbostart as a spare. I believe you should be reading around 19 volts with charger connected and battery fully charged.

Why not search the net for the owners manual for the charger(s) you have? It should have the specs.

load tester

our Schumacher 16V charger did the same thing , same scenario. thought the battery was acting up ..... ... took it apart at the nats at Indy and found a burned up connection , found the parts at Autozone , and fixed it ...might be worth a look inside .....

The Autometer 16 volt maintainer has worked great for me for 9 years now.